New to the bike gang

[bike4life]

+Marc 20:
(1) brazing can be "tricky". Higher skill level involved and a lot of patience. If you have a standard blue propane torch, good luck heating a heavy lb aluminum mass to 1000* for brazing. Aluminum is used in heat sinks and cools down fast, its hard to get a large work peace up to temperature to braze with a weaker torch.

(2) brazing is meant for non-structural applications. It is very weak compared to a weld, as it kind of glues the metal together via capillary action and crap and not actual weld fusion....

+Frogslayer
The reason why aluminum is used in space and aviation is because of weight...
Weight matters when your in the air, not so much when traveling on flat ground. Freight trains boast a 450 Miles per gallon per ton of freight, yet the are really overbuilt and heavy compared to trucks and stuff. Yes the steel wheels help a lot, but the real fuel savings come from aerodynamics at speeds greater than 30MPH... Air is actually a fluid, and takes a lot of energy to move around... Think of a 1hp blower motor, spending 1000 watts of energy just to move a 100 cubic feet of air around, when you can put that same motor on a bicycle and go 30mph.
Also. Cause you have to expend energy so that weight doesn't fall back down from gravity, and to increase elevation, potential energy.... So weight counts there otherwise your going to just fall down to the ground if your wing profile cannot generate enough lift.
Plus fuel is hella hella expensive, so they can justify using different exotic materials and stuff to save a little bit on fuel...

 

[Vikingimike01]

Air is actually a fluid, and takes a lot of energy to move around...

THANK YOU!!! I have been thinking a lot about this! It behaves a LOT like fluid except its compressable. the mass of air is about 12,5 newtons per square meter or about 10 square feet! Thats almost 3 pounds of air. That you have to cut trough and move!! Now imagine holding up a 50cm x 50cm or 1.6 x 1.6 feet of steel sheet at 15kmh or 10mph. Its hard to hold it!!! Is it not?? Now bend it in an arrow shape halfway trough the middle. Not so much now? Yeah. Imagine that at 35kmh / 20mph or even 50kmh / 30mph!!!

 

[FurryOnTheInside]

So if the OP wants to go 40mph using his "Zeda PK80" (Not sure what that is.. kinda thought the PK80 was a different engine not even made by JLZeda!) should he just do some research by actually reading the forum or wait to be spoon fed, and any missing information is our fault?

BTW my bike is alloy and yet can do 40mph on Thursdays. It has a Crappy Time generic engine and non-expansion muffler pipe with stock carburettor, and it was my first and only ham-fisted attempt at porting. With a cheap, like £10!, rotary tool.
I just read what people already put the effort into writing out and posting on the forum for everyone to read. Took notice of the important points. Copied the work of others. Had some success.

The bike cost about £2000 or $2500 to put together, mainly for the tools to build it, and repeated purchases of this and that, stuff that didn't fit, or turned out to be unsuitable or unsafe.. or i just changed my mind!
But a lot of it went on the safety equipment like reliable brakes and strong wheels and thick puncture resistant tyres, and the things that DON'T MAKE IT ANY FASTER.
I'll try to make it faster soon, now its ready for that.

The PK80 and Zeda80 are powerful enough to get 40mph with zero modifications, straight "out the box", are they not?

I think making a crappy Walmart bike-shaped-object with stamped single-pivot long-reach U "brakes" and cheap tyres with off-road tread go at 40mph+ is just foolhardy and irresponsible, even nearly funny... but its your spleen.

 

[Vikingimike01]

have you heard of heel brakes, furry? lol. (but really tho that made me think of putting brake pads on my heels, i have weird thoughts)
i may try that one day

 

[bike4life]

I am sure furry that your alloy bike will be ok... I doubt it will ever break catastrophically. These bikes have safety factors in them so the lawyers don't go crazy...
You know the world record for bike riding is like 150mph and that was carbon fiber i think, which is much weaker than aluminum... But its just that steel is stronger.... Its just for peace of mind i'd suppose... And b/c steel is cheaper than aluminum frames, then why not....

 

[FurryOnTheInside]

have you heard of heel brakes, furry? lol. (but really tho that made me think of putting brake pads on my heels, i have weird thoughts)
i may try that one day

I have used toe-jam braking on a bike that came with terrible brake set-up and I needed to ride it home to fix it.
I'd rather toe-jam the front tyre than put my heels to the pavement.
I put front brakes on even for riding dirt jumps. Have to ride TO the jumps to ride them.

I crashed enough over the years. Knees are pretty wrecked from all the lowsides but I rarely went otb without doing it deliberately, using the eject button, to avoid a heavy steel object.. not by actually hitting the heavy steel objects!
There's only the front brake to do that. No heel braking will give you the power and split second control to throw yourself cleanly over a car at 40mph. the alternative option: hit the car. with. your. body. bones. flesh. spleen. face.

No, I say get a freaking good bike, make it worthy of our slow motorcycle but wayy fast bicycle speeds. Get good at riding in safe areas. Push the limits in comparative safety to develop skill. Then go out and have a decent chance of surviving at your average speeds. Wear your helmet. Different helmets for different purposes. Expense is not a factor here.

Expense... BTW it cost me nothing to read up on the forum. Its a very interesting story. You can start at page one. The development of the Shift Kit is a good story of cooperation and kindly constructive contribution, by our community as it was at the time, helping it progress. Knowing we obviously have to pay for the parts (and make the project succeed commercially to some extent) if we want them, we made sure they were of a suitable design! I say "we" but had not joined the community at this forum until later.

I have weird thoughts too. I have just started taking a new antipsychotic! Yay! Working on being less over-excited. The music sounded better without them, though. Or maybe its something else doing that to me. Hard to tell with brain diseases though! lol.

 

[FurryOnTheInside]

I am sure furry that your alloy bike will be ok... I doubt it will ever break catastrophically. These bikes have safety factors in them so the lawyers don't go crazy...
You know the world record for bike riding is like 150mph and that was carbon fiber i think, which is much weaker than aluminum... But its just that steel is stronger.... Its just for peace of mind i'd suppose... And b/c steel is cheaper than aluminum frames, then why not....

Eric Barone, yes. The bike was alloy with a carbon composite fairing. Downhill on a snow slope. 149.499mph.

The gravel top speed attempt was less successful. The bike broke up at around 107mph on a slope of volcanic pumice. He went down hard and he ate a bunch of it.
I think he still hit 140mph during his fall..

I would say that steel is great for specific applications and totally recycleable. It is great in tension. Bolts. What we call spokes but are actually suspenders. The suspenders on suspension bridges are steel, just like a bicycle wheel. In fact I'm not sure which was the basis for which!

Aluminium alloy is great for other specific applications and can be recycled. It is great in compression. It does work harden if you flex it repeatedly. We can make our engines vibrate much less. Also ride multiple bikes less, to extend the life of each. Mainly though, do a good enough job of mounting the engine, taking account of all our knowledge and good mechanical sense. My bike won't fail catastrophically during my remaining lifetime unless I go riding down volcanoes lol.

A carbon and resin composite is ideal for the sake of helping the record breaking attempts and winning at races. It is impossible to recycle. It becomes landfill. It is strong used in the way it was designed but weak under unexpected loads and abrasion.

I bought one new carbon bike part: a rim for the front wheel because the "added lightness" is noticeable there.
Some used carbon composite parts like seapost and bars.
And a few cheaper carbon/graphite composite fishing rods.

 

[refuge33]

The suspension is not really necessary. Also adds extra weight!
He already has a kit, I doubt he will get a new kit (also the bt100 and the other one arent much stronger)
Most "aftermarket" exhaust pipes do nothing. What do you mean by decent? Lol. For all we know he will get something thats expensive but does nothing. There are a lot of expensive pipes that don't do anything.
What do you mean by fuel additives? Only oil?
You listed strong and lightweight bike twice
how can he have two rear sprockets?

when you hit a pothole at 45=, you will appreciate having front suspension.
I bought a set of jets and experimented until I found the best fit,
I bought a $22.oo banana pipe that gives much more power than the stock muffler and not much louder,
I use 93 octane fuel from a local gas station that sells it, I use Pennzoil racing 2 stroke oil with a teaspoon of 104 Octane booster, and mix it thoroughly,
I was using a 40 tooth but got another rim and mounted a 32 tooth and keep it handy to just swap out when needed,
and my bike with the engine is close to some of the others that have those steel frames without an engine,
Power to weight is also bodyweight, I weigh 145lbs and that's why it is so fast. I have mounted Zeda triple 40's on other type mountain and cruiser bikes and just the sheer weight of them drops top speed by at least 4-9mph alone, and finally I have logged over 4500 miles on aluminum frames, hit potholes bigger than the Grand Canyon at speed, and never had any type of frame damage or cracks, so whatever flicks your switch....

 

[Vikingimike01]

when you hit a pothole at 45=, you will appreciate having front suspension.
I bought a set of jets and experimented until I found the best fit,
I bought a $22.oo banana pipe that gives much more power than the stock muffler and not much louder,
I use 93 octane fuel from a local gas station that sells it, I use Pennzoil racing 2 stroke oil with a teaspoon of 104 Octane booster, and mix it thoroughly,
I was using a 40 tooth but got another rim and mounted a 32 tooth and keep it handy to just swap out when needed,
and my bike with the engine is close to some of the others that have those steel frames without an engine,
Power to weight is also bodyweight, I weigh 145lbs and that's why it is so fast. I have mounted Zeda triple 40's on other type mountain and cruiser bikes and just the sheer weight of them drops top speed by at least 4-9mph alone, and finally I have logged over 4500 miles on aluminum frames, hit potholes bigger than the Grand Canyon at speed, and never had any type of frame damage or cracks, so whatever flicks your switch....

First, the suspension is not NECESSARY for hitting that speed. It adds weight. Of course its good to have one, I want to get one later, but I had no problems without one. You gotta look out for potholes. Don't even think about going fast on a bad road... this is common sense

The banana pipe does NOT give more power. All it does is you can rev a little higher. I have one as well.

Its also really fast to just swap out the sprocket, you don't need to buy a new rim.. Just get 1 good rim, with 3mm spokes, and get a CNC adapter if you wanna switch sprockets so often.

 

[Regalgse00]

So would just a basic expansion chamber exhaust give you more power. I don’t really like putting on some exhaust off a scooter or anything. Just something simple from BikeBerry or something to get a little more power with.?